Folded cascode current source with dual mirrors current feedback

A high performance BJT current source in a folded cascode configuration is shown to achieve high output resistance, wide voltage swing and wide-band frequency response. The design employs dual pnp-npn current mirrors for current feedback between the base and the emitter in order to maintain the constant collector current. Simulation results show that the performance of the proposed folded cascode current source is superior to the conventional current sources, achieving for example an output resistance of 71MΩ and an impedance bandwidth product of 2.8TΏ-Hz at 1mA output current and 1.6V input voltage. The proposed scheme can be implemented with MOSFETs and also provide for an efficient design in current feedback amplifiers.